The reaction products of phenol or derivatives thereof with formaldehyde or reactive equivalents thereof are well known. See, e.g., Peter W. Kopf, "Phenolic Resins", Encyclopedia of Polymer Science and Engineering, vol. 11, pp. 45-94 John Wiley & Sons, N.Y., 1988. These resins may be used as binders in various inks and coatings, however their use is somewhat limited by their high cost. Less expensive phenolic-type resins are prepared when rosin is included among the reactants that form a phenolic resin. These so-called "rosin-phenolic" resins are widely used today in lithographic printing processes. See, e.g., Roger E. Burke, "Rosin-based Printing Inks", Naval Stores, Chapter 10, Pulp Chemicals Association (1989).
However, the increasingly popular use of rosin in other applications, such as tackifiers and other types of resins for various printing and coating processes, has increased competition for an essentially fixed amount of rosin, and increased the incentive to use alternatives to rosin-phenolic resins.
A by-product of the sulfate pulping process is crude tall oil (CTO), and a by-product of CTO fractionation is distilled tall oil (DTO). DTO is an impure material, containing at least three major classes of components. DTO does not have the resin acid content of rosin, nor the fatty acid content of TOFA, where rosin and TOFA are both obtained from CTO and have both found many commercial applications. Instead, DTO is an ill-defined mixture of various thermally-induced isomerization and dimerization products. To date, DTO has not received great commercial acceptance.
Accordingly, there is a need in the art for useful products that can take advantage of the unique composition and reactivity of DTO. There is also a need in the art for processes that can be used to convert/incorporate DTO into useful products. There is a further need in the art for viable alternatives to rosin-phenolic ink resins. The present invention addresses these long-standing needs, and provides other related advantages, as discussed below.